There is a progressively increasing awareness of the acoustic pollution caused by marine seismic surveys. The risk of causing hearing damage in marine mammals is currently mitigated by the ‘exclusion zone’ around the seismic source and by the prohibition of seismic surveying in some areas at certain times of the year. Such limitations are likely to become more onerous as exploration moves to more extreme latitudes. Recently an agreed set of criteria has been published for estimating hearing damage in marine mammals.